Half to charles j



(No Model.)

W. H. BIRCH.

SHBAVE.

No. 425,734. Patented Apr. 15. 1890.

V UNITED STATES PATENT OFFICE.

IVILLIAM H. BIRCH, OF SAN FRANCISCO, CALIFORNIA, ASSIGNOR OF ONE- I'IALF TO CHARLES J. KAIGHIN, OF SAME PLACE.

SH EAVE.

SPECIFICATION forming part of Letters Patent No. 425,734, dated April 15, 1890. Application filed December 20, 1889. Serial No. 334,427. (No model.)

To aZZ whom it'may concern:

Be it known that I, VVILLIAM l-I. BIRCH, a citizen of the United States, residing in the city and county of SanFrancisco, State of California, have invented an Improvement in Sheaves; and I hereby declare the following to be a full, clear, and exact description of the same. I

My invention relates to the class of sheaves or pulleys; and it consists in the novel improved construction thereof, hereinafter fully described, and specifically pointed out in the claims.

The object of my invention is to provide a sheave having a separc ble or detachable easily-renewable wearing-surface, whereby the body of the sheave may be preserved indefinitely.

Though my improved sheave may be used in any place or connection, it is especially of value in the construction and maintenance of cable roads, being adapted for use in the tension-carriage, at all places where a change of direction of the rope is had, at the terminus 2 5 of the road where the rope returns, and wherever there is particular strain and wear of the cable. In these and similar places the sheaves always wear out on their rims, and'they then have to be entirely renewed-a difficult and expensive proceedingand in the operation of cable roads a delay is caused,'the'effect of which is to tie up the entire road. My invention avoids this necessity, and also gives other advantages, which will be presently pointed 3 5 out.

Referring to the accompanying drawings for a more complete explanation of my invention, Figure 1 is a side elevation of one-half of my sheave. Fig. 2 is a cross-section of the rim and separable or detachable segments thereof, the latter being shown as slightly removed from the rim for better illustration.

The sheaveA is formed of the usual hub a, arms a, and complete grooved rim B. On 5 each side of the rim is formed a flange b. C

are separable or detachable independent segments. These are formed with a base adapted to be fitted properly in thegroove of rim B, a groove 0 in their face, and side flanges c, which fit on the flanges b of the rim. These segments may be of any desired length, and they are suflicient in number to extend around the entire periphery of the rim B and form the wearing-surface of the sheave. They are secured to the rim by means of bolts D, passing through the side flanges Z) and c, the heads of said bolts being countersunk, in order to avoid any projecting points or portions which might catch the clothes of a person working at or about the sheave.

It will be readily seen from the foregoing that an improved sheave of this kind will obviate the main disadvantages heretofore mentioned. It can be used continuously until the segments wear down, and even then, if the sheave cannot be immediately attended to, no injury will result for an appreciable time, for the reason that the rim B itself will serve for the rope. This feature of having a complete and operative rim, which can and will come into action when the segments are worn down, is of prime importance in cable roads, for these sheaves are generally located in obscure places and situations difficult of access.

\Vith my sheave the necessity of immediate 7 5 attention is not present, for the rim B will. serve for the rope after the segments are worn down. Again, when using the ordinary sheave, the tendency of the rope is to cut off one of the walls or sides of the grooved face of the rim, and to drop down onto the hub or other parts of the structure and be thereby injured. IVith my sheave this does not occur. When the segments are worn,they canbe easily removed and others substituted,thus making the body of the sheave last indefinitely.

The particular construction of the rim with its side flanges and that of the segments with their side flanges are to be noticed as furnishing practical means of uniting them, leaving the groove of the segments clear of all boltheads, whereby it can wear uniformly and not injure the rope.

In practice the sheave is of cast-iron. The segments being small pieces, comparatively, are made of very close iron, and are consequently harder than the sheaverim. A very important advantage of this construction lies in the provision of such a thick wearing-surface as is shown. Such thickness would not too be practicable in the rim itself, for in casting it the shrinkage would be so unequal as to tively small segments may be cast smooth in their grooves, thereby preserving the skin and adding to their wearing qualities.

I am aware of that improvement in the manufact-nre of pulleys which contemplates the use of a separable spider and rim; but this is not like my invention, for I propose to use a complete sheave composed of hub, arms, and rim, which gives me the advantage of the rim strength and endurance, and to this complete device I apply my wearing-segments.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is

1. An improved sheave formed with a complete rim and laterally-projecting side flanges,- and separable or detachable grooved and flanged segments secured to the face of said rim on each side, and forming a renewable wearing-surface for the sheave, substantially as herein described.

2. An improved sheave formed with a complete rim having a groove in its face and laterally-projecting side flanges, and separable or detachable segments fitted in the groove of the rim and forming a renewable wearing-surface for the sheave, said segments having a thick wearing-surface at their bases, substantially as herein described.

An improved sheave formed with a complete rim havinga grooved face and separable substantially as herein describe 5. An improved sheave formed with a complete rim with a grooved face and a flange on each side, separable or detachable segments,

each provided with a deeply-grooved face fitted in the grooved face of the rim and forming a renewable wearing-surface for the sheave, saidsegments having side flanges fitting on the flanges of the rim, and bolts securing said flanges together, and having their headscoum tersunk in the flanges of the segments, substantially as herein described.

In Witness whereof I have hereunto set my hand.

WVILLIAM H. BIRCH.

Witnesses:

' S. H. NOURSE,

I-I.'C. LEE. 

